It has been found that when the pneumatic and/or dynamic brakes on a railway locomotive or train are applied, the amount of actual braking force must be carefully controlled in order to safely and effectively slow down and/or stop the railway train at the entrance of a signal block or at a station or the like. Under conditions of a clean dry rail, the wheel-rail friction or adhesion is usually sufficient to maintain wheel rotation under normal braking forces. However, oil, wet or other slippery substances on the rails can upset the wheel-rail friction so that during braking the force acting to keep the wheels rolling deteriorates to the point where wheel slip occurs. It will be appreciated that once the wheel starts to slip, it rapidly progresses to a slide condition in which a sudden wheel lockup occurs. It has also been found that under certain conditions, a penalty, an emergency and in some circumstances, a service braking application may result in a slipping condition which could rapidly and inevitably progress from slipping to sliding with a resultant wheel lockup which produces flat spots on the sliding wheel and tends to lengthen the stopping distance of the train. Moreover, the repair and replacement of worn or flat wheels is an item of great concern to the maintenance department of the railroad or transit operators. It is well known that sanding is an effective method for assuring that adequate adhesion exists between the wheels and rails during the braking of the railway vehicles. However, many of the previous sanding methods relied upon the intuition and judgement of the engineman or operator in the application of the sand. Even with the development of more sophisticated electrical and mechanical equipment, there is a need to improve the method and manner of sanding the rails to ensure the existence of adequate wheel-rail adhesion during the braking of the moving vehicles. Now with the advent or increased usage of microprocessors and minicomputers onboard of locomotives and transit vehicles, it is possible to effectively and efficiently control and prevent the wheels from slipping and/or sliding during the various types of brake applications.